January 17, 2017
Introduction
Julia
had some study on Leetcode 17 - a phone
number algorithm, one of studies is on stack/ queue
implementation of the algorithm in May 2016. After more than 6 months, in
January 2017, she worked on suffix
rotation algorithm in
the contest, she made a mistake to choose using queue instead of stack.
So,
after the week code 28 contest, in 1 - 2 day, she studied suffix rotation's
test case provided by hackerrank: a string "lcatqjejhpgkrkhnxsfyqlulncefeytykwnqbfmqaduldwhgwruwkdvojexefcmfrlfuzzcurjgnnbkskbzw",
the code has issues related to out-of-memory, queue size is over 11,387,997, 10
millions, stop after processing first 12 chars "aaabbbbbccc", over
one minute at least.
code
with bugs is here.
Suffix Rotation C# practice, with a bug running out of
memory.
Problem Solving
Thank
you, a small test case helps me to understand the issue again. Queue vs Stack,
for phone number less than 7 digits, queue is still ok - not causing
out-of-memory issue. But with string with length over 20, the problem quickly
comes out easily.
lcatqjejhpgkrkhnxsfyqlulncefeytykwnqbfmqaduldwhgwruwkdvojexefcmfrlfuzzcurjgnnbkskbzw
Remember this test case, as a programmer, Julia has to work on a test case more often; build a good habit to figure out issues in the design with help of test cases, specially in any hackerrank contest. Kind of boring talk, let us talk about a song.
The solid Rock, corner stone or sinking sand
Julia has a favorite song she likes to sing along a lot of times, specially a lot of years ago (2000 - 2010) in Boca Raton
Related to being a hackerrank contest player, Julia has some
hope, the test case can be her solid rock if she has weakness in the design, and flaws in thinking process.
The test case is the solid Rock, I stand;
All other ground is sinking sand,
All other ground is sinking sand.
Code review study
Julia chooses to study more on phone number related
algorithms.
1. Code review: Phone number.
2. Very good Dynamic programming explanation, read the phone
number's code review
by Google engineer.
3. Phone number code review - group of 3
digits with no lone digits.
At last, review algorithm code review made by a google engineer, click here.
